Conclusions and Prospects

Throughout the book, I have been searching for empirical examples and theories dealing with how perturbations trigger behavioural feedback responses in social animals, how these responses affect the decision to disperse between patches, and the consequences of dispersal for complex, nonlinear population dynamics. What seems quite clear is that social feedbacks—and especially runaway dispersal by copying—do play an important role in those responses, compared to solitary species. Although philopatry to the patch has many benefits, perturbations may decrease the suitability of this patch. When a patch is perturbed, do social species show different responses than solitary species? Since evolution has selected for maximizing fitness prospects, individuals living either in groups or in solitary will try to avoid the detrimental effects of the perturbation, for instance by leaving the patch. The behavioural mechanisms triggered by perturbations are similar for both social and solitary species: increase of information gathering to reduce uncertainty and the use of this updated information to make optimal decisions about either staying or leaving. Thus, the answer is that solitary and social species show similar responses to perturbations. Nevertheless, the way those behavioural mechanisms operate is rather different between social and solitary species: in the former, information is shared among individuals, and decisions about when to leave the patch and where to go are made not only using private or personal information, but mostly using social information. Last but not least, there is social copying, a trend to copy in a nonrational way what others have decided before. This social copying, also called conformity, may trigger what I termed runaway dispersal: perturbations may accumulate over time, decreasing resilience of the social group until attaining a tipping point. Once this threshold is surpassed, the decision to disperse is led by a few individuals, and this decision is copied by the rest of the group in an autocatalytic way....